Download Shure SM81 Microphone Specification Sheet

Model Model SM81 Microphone
Specification Sheet
MODEL SM81
UNIDIRECTIONAL CONDENSER MICROPHONE
OVERVIEW
The Shure Model SM81 is a high-quality, unidirectional condenser microphone designed for studio recording, broadcasting,
and sound reinforcement. Its wide frequency response, low
noise characteristics, and low RF susceptibility have made it a
standard for applications involving acoustic instruments, especially guitar, piano, and cymbals.
The SM81 is ruggedly constructed. It operates on phantom
power and performs over a wide range of temperatures and humidity conditions. It is furnished with a swivel adapter, attenuator-switch lock, foam windscreen, and case for carrying and storage. Other accessories are available.
FEATURES
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20 Hz to 20 kHz frequency response
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Low RF susceptibility
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Flat response curve for accurate reproduction of sound
sources
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Selectable low-frequency response: flat, 6 or 18 dB/octave
rolloff
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Low noise and high output clipping level
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0 dB/10 dB lockable attenuator switch
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Low distortion over a wide range of load impedances
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Phantom powering (DIN 45 596 voltages of 12 to 48 Vdc)
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Cardioid polar pattern, uniform with frequency and symmetric about axis, providing maximum rejection and minimum
coloration of off-axis sounds
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Rugged steel construction for durability
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Field-usable over wide range of temperature and humidity
conditions
SPECIFICATIONS
Type
Polar Pattern
Cardioid (unidirectional) response—uniform with frequency, symmetrical about axis (see Figure NO TAG)
Condenser (electret bias)
Frequency Response
180o
20 to 20,000 Hz
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150o
180o
120o
120o
150o
150o
150o
120o
120o
dB
+10
90o
90o 90o
0
1 METER
–10
2
20
50
100
3 4 5 6 789
1000
Hz
2
3 4 5 6 789
10000 20000
TYPICAL FREQUENCY RESPONSE
90o
–20 dB
–20 dB
–15 dB
–15 dB
60o
60o
–10 dB
60o
–5 dB
–5 dB
30o
30o
0
1 kHz
500 kHz
100 Hz
60o
–10 dB
30o
30o
2 kHz
0
5 kHz
10 kHz
TYPICAL POLAR PATTERNS
MODEL SM81 CONDENSER MICROPHONE
Output Impedance
Rated at 150 ohms (85 Ω actual)
Recommended minimum load impedance: 800 Ω (May be
used with loads as low as 150 Ω with reduced clipping
level)
Output Configuration and Connector
Balanced, transformer-coupled output; male XLR connector
Specification Sheet
Reverse polarity protection . . . . . . . . . . . . 200 mA max.
(diode-clamped)
Polarity
Positive pressure on diaphragm produces positive voltage
on pin 2 relative to pin 3
Cartridge Capacitance
54 pF
Low Frequency Response Switch Positions
Sensitivity (at 1,000 Hz)
Open Circuit Voltage . . . . . . . –45 dBV/Pascal (5.6 mV)
(1 Pascal = 94 dB SPL)
Flat; –6 dB/octave below 100 Hz; –18 dB/octave below 80
Hz
Clipping Level (at 1,000 Hz)
Attenuator Switch Positions (Lockable)
800 Ω Load . . . . . . . . . . . . . . . . . . . . . . . –4 dBV (0.63 V)
150 Ω Load . . . . . . . . . . . . . . . . . . . . . . –15 dBV (0.18 V)
0 or –10 dB
Power
Total Harmonic Distortion
Supply Voltage . . 11 to 52 Vdc, positive, pins 2 and 3
Current Drain . . . . . . . . . . . . . . . . . . . . . . . . 1.2 mA max.
Less than 0.5% (131 dB SPL at 250 Hz into 800 Ω load)
Maximum SPL (at 1,000 Hz)
Environmental Conditions
800 Ω load . . . . . . . . . . . . . . . . 136 dB (attenuator at 0)
146 dB (attenuator at –10)
150 Ω load . . . . . . . . . . . . . . . . 128 dB (attenuator at 0)
138 dB (attenuator at –10)
Hum Pickup
–3 dB equivalent SPL in a 1 mOe field (60 Hz)
Self-Noise (equivalent sound pressure levels; measured with
true rms voltmeter)
16 dB typical, A-weighted
19 dB typical, weighted per DIN 45 405
Temperature:
Storage . . . . . . . . . . . . . . . . . . . . . . . – 29_ to 74_ C
(–20_ to 165_ F)
Operating . . . . . . . . . . . . . . . . . . . . . . – 6.7_ to 49_ C
(20_ to 120_ F)
Humidity:
Storage . . . . . . . . 0–95% relative humidity at room
temperature (72_to 80_ F, 22_ to 27_ C)
Case
Steel construction with vinyl metallic paint finish and stainless steel screens
Signal-to-Noise Ratio
78 dB (IEC 651)* at 94 dB SPL
Dimensions
*S/N ratio is difference between microphone output at 94 dB SPL
and microphone self-noise A-weighted.
See Figure NO TAG
Weight
Overvoltage and Reverse Polarity Protection
Net . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230 grams (8 oz)
Packaged . . . . . . . . . . . . . . . . . . 740 grams (1 lb 10 oz)
Max. external voltage applied to pins 2 and 3 with
respect to pin 1 . . . . . . . . . . . . . . . . . . . . . . + 52 Vdc
FURNISHED ACCESSORIES
Swivel Adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A57F
10 dB Attenuator Lock . . . . . . . . . . . . . . . . . . . . . . . . . 34A830
Carrying/Storage Case . . . . . . . . . . . . . . . . . . . . . . . 65A1797
Windscreen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49A111
REPLACEMENT PARTS
Cartridge and Grille Assembly . . . . . . . . . . . . . . . . . . . R104
OPTIONAL ACCESSORIES
Pop-Filter Grille . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A81G
Heavy-Duty Windscreen . . . . . . . . . . . . . . . . . . . . . . . A81WS
Tripod Microphone Stand (4.3 m [14 ft]) . . . . . . . . . . . . S15A
Stereo Microphone Adapter . . . . . . . . . . . . . . . . . . . . . . A27M
Cable (7.6m [25ft]) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C25F
Phantom Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . PS1A
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